The Americans with Disabilities Act (ADA) requires the removal of physical obstacles to those who are physically challenged. The stated objective of this legislation has increased public awareness and concern over the requirements of the physically challenged. Consequentially, there has been more emphasis on providing systems that enable physically challenged people to access a motor vehicle, such as a bus or minivan.
A common manner of providing the physically challenged with access to motor vehicles is a ramp. Various ramp operating systems for motor vehicles are known in the art. Some slide out from underneath the floor of the vehicle and tilt down. Others are stowed in a vertical position and pivot about a hinge, while still others are supported by booms and cable assemblies. The present invention is generally directed to a “fold out” type of ramp. Such a ramp is normally stowed in a horizontal position within a recess in the vehicle floor, and is pivoted upward and outward to a downward-sloping extended position. In the extended position, the ramp is adjustable to account for various curb heights.
Fold out ramps on vehicles confront a variety of technical problems. One such technical issue arises from the variety of situations in which the ramps must operate. Depending on the use of the vehicle in which a particular ramp is installed, the ramp might be deployed to curbs of varying heights, as well as to a road surface. In addition, road crown, the inclusion of a “kneeling” feature on the vehicle, and other factors can affect the height of the vehicle floor relative to the alighting surface. Thus, the vertical distance through which a ramp must provide a transition surface can vary significantly.
One attempt to provide a longer ramp surface to reduce the ramp angle in a variety of situations is disclosed in U.S. Patent Publication No. 2011/0268544 (“the '544 publication”), by Koretsky et al., which published on Nov. 3, 2011, the entire disclosure of which is incorporated herein by reference. The '544 publication discloses a ramp assembly that includes a self-aligning platform mechanism. The platform mechanism includes a deploying mechanism connected between a hinged platform and a ramp. The mechanism automatically aligns the ramp with the platform to assure the same angle of both components in relation to the ground surface for a low floor vehicle access ramp regardless of the height of the vehicle floor and the pivot axis of the ramp, with respect to the ground surface or curb. To ensure that the platform and the ramp deploy to the same angle in relation to the ground surface, the ramp assembly has a switch disposed on the ramp. When the ramp reaches an aligned position with respect to the platform, i.e., when the ramp surface is parallel to the platform surface, the switch is actuated to stop the motor of the drive system.
While certain advantages are provided by ensuring that the ramp surface aligns with the platform surface when the ramp assembly is deployed, such a configuration also presents disadvantages. Some such disadvantages arise from the typical placement of a ramp assembly in a bus.
Ramp assemblies such as the one disclosed in the '544 publication are commonly installed at the front of a bus so that the ramp extends laterally toward the curb to provide a sloped transition surface between the interior of the bus and an alighting surface, such as a curb. To enter the bus, a disabled passenger travels up the inclined surface and then turns at the top of the ramp into the aisle of the vehicle. To exit the bus, the disabled passenger moves up the aisle until aligned with the ramp and then turns toward the curb and exits down the inclined surface. Passengers entering or exiting a bus will often “cut the corner” between the inclined surface and the vehicle aisle. That is, a passenger entering the bus may start to turn into the vehicle aisle while still positioned on the inclined surface. Similarly, a passenger exiting the bus may turn toward the curb before he or she is far enough forward in the aisle. In both cases, the drop off formed between the vehicle floor and side of the inclined surface of the deployed ramp assembly presents an obstacle to the passenger. For a passenger entering the bus, prematurely turning into the vehicle aisle requires the passenger to navigate up and over the lip, which can cause difficulty for passengers in wheelchairs, using walkers, or with otherwise limited mobility. For a passenger exiting the bus, prematurely turning onto the inclined surface can cause the passenger to drop off of the vehicle floor onto the inclined surface.
In view of the noted disadvantages that can accompany ramp assemblies like the one disclosed in the '544 publication, it would be advantageous to minimize the slope of the roadside portion of the deployed ramp assembly, while keeping the curbside portion of the deployed ramp assembly below a predetermined maximum slope. Minimizing the slope of the roadside portion of the deployed ramp assembly reduces the height of the drop off formed between the vehicle floor and the inclined surface, while keeping the curbside portion of the deployed ramp assembly below a predetermined maximum slope makes the ramp easier to navigate.